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Multimedia, IEEE Transactions on

Issue 3 • Date Sep 2002

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Displaying Results 1 - 8 of 8
  • Image quality evaluation based on recognition times for fast image browsing applications

    Publication Year: 2002 , Page(s): 320 - 331
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (387 KB) |  | HTML iconHTML  

    Mean squared error (MSE) and peak signal-to-noise-ratio (PSNR) are the most common methods for measuring the quality of compressed images, despite the fact that their inadequacies have long been recognized. Quality for compressed still images is sometimes evaluated using human observers who provide subjective ratings of the images. Both SNR and subjective quality judgments, however, may be inappropriate for evaluating progressive compression methods which are to be used for fast browsing applications. In this paper, we present a novel experimental and statistical framework for comparing progressive coders. The comparisons use response time studies in which human observers view a series of progressive transmissions, and respond to questions about the images as they become recognizable. We describe the framework and use it to compare several well-known algorithms (JPEG, set partitioning in hierarchical trees (SPIHT), and embedded zerotree wavelet (EZW)), and to show that a multiresolution decoding is recognized faster than a single large-scale decoding. Our experiments also show that, for the particular algorithms used, at the same PSNR, global blurriness slows down recognition more than do localized "splotch" artifacts. View full abstract»

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  • Smart rebinning for the compression of concentric mosaic

    Publication Year: 2002 , Page(s): 332 - 342
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB) |  | HTML iconHTML  

    The concentric mosaic offers a quick solution to construct a virtual copy of a real environment, and to navigate in that virtual environment. However, the huge amount of data associated with the concentric mosaic is a heavy burden for its application. A three-dimensional (3D) wavelet-based compressor has been proposed in a previous work to compress the concentric mosaic. In this paper, we greatly improve the compression efficiency of the 3D wavelet coder by a data rearrangement mechanism called "smart rebinning". The proposed scheme first aligns the concentric mosaic image shots along the horizontal direction and then rebins the shots into multiperspective panoramas. Smart rebinning effectively enhances the correlation in the 3D data volume, translating the data into a representation that is more suitable for 3D wavelet compression. Experimental results show that the performance of the 3D wavelet coder is improved by an average of 4.3 dB with the use of the smart rebinning. The proposed coder outperforms MPEG-2 coding of the concentric mosaic by an average of 3.7 dB. View full abstract»

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  • Robust progressive image transmission over OFDM systems using space-time block code

    Publication Year: 2002 , Page(s): 394 - 406
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (535 KB) |  | HTML iconHTML  

    A joint source-channel coding (JSCC) scheme for robust progressive image transmission over broadband wireless channels using orthogonal frequency division multiplexing (OFDM) systems with spatial diversity is proposed for the application environments where no feedback channel is available such as broadcasting services. Most of current research about JSCC focuses on either binary symmetric channels (BSC) or additive white Gaussian noise (AWGN) channels. To deal with fading channels in most previous methods, the fading channel is modeled as two state Gilbert-Elliott channel model and the JSCC is normally aimed at the BER of bad channel status, which is not optimal when the channel is at good status. By using diversity techniques and OFDM, the frequency selective fading effects in broadband wireless channels can be significantly decreased and we show that subchannels in OFDM systems approach Gaussian noisy channels when the diversity gain gets large; as a result, the system performance can be improved in terms of throughput and channel coding efficiency. After analyzing the channel property of OFDM systems with spatial diversity, a practical JSCC scheme for OFDM systems is proposed. Simulation results are presented for transmit diversity with different numbers of antennas and different multipath delay and Doppler spread. It is observed from simulations that the performance can be improved more than 4 dB in terms of peak signal-to-noise ratio (PSNR) of the received image Lena and the performance is not very sensitive to different multipath spread and Doppler frequency. View full abstract»

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  • Techniques and data structures for efficient multimedia retrieval based on similarity

    Publication Year: 2002 , Page(s): 372 - 384
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (291 KB) |  | HTML iconHTML  

    As more and more information is captured and stored in digital form, many techniques and systems have been developed for indexing and retrieval of text documents, audio, images, and video. The retrieval is normally based on similarities between extracted feature vectors of the query and stored items. Feature vectors are usually multidimensional. When the number of stored objects and/or the number of dimensions of the feature vectors are large, it will be too slow to linearly search all stored feature vectors to find those that satisfy the query criteria. Techniques and data structures are thus required to organize feature vectors and manage the search process so that objects relevant to the query can be located quickly. This paper provides a survey of these techniques and data structures. View full abstract»

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  • Effective wipe detection in MPEG compressed video using macro block type information

    Publication Year: 2002 , Page(s): 309 - 319
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (425 KB) |  | HTML iconHTML  

    For video scene analysis, the wipe transition is considered most complex and difficult to detect. In this paper, an effective wipe detection method is proposed using the macroblock (MB) information of the MPEG compressed video. By analyzing the prediction directions of B frames, which are revealed in the MB types, the scene change region of each frame can be found. Once the accumulation of the scene change regions covers most of the area of the frame, the sequence will be considered a motionless wipe transition sequence. Besides, uncommon intracoded MB of the B frame can also be applied as an indicator of the motion wipe transition. A very simple analysis based on small amount of MB type information is sufficient to achieve wipe detection directly on MPEG compressed video. Easy extraction of MB type information, low-complexity analysis algorithm and robustness to arbitrary shape and direction of wipe transitions are the great advantages of the proposed method. View full abstract»

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  • On the design of content-based multimedia authentication systems

    Publication Year: 2002 , Page(s): 385 - 393
    Cited by:  Papers (34)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (345 KB)  

    Recently, a number of authentication schemes have been proposed for multimedia data. The main requirement for such authentication systems is that minor modifications which do not alter the content of the data preserve the authenticity of the data, whereas modifications which do modify the content render the data not authentic. These schemes can be classified into two classes depending on the underlying model of image authentication. We look at some of the advantages and disadvantages of these schemes and their relationship with limitations of the underlying model of image authentication. In particular, we study feature-based algorithms and hash-based algorithms. The main disadvantage of feature-based algorithms is that similar images generate similar features, and therefore it is possible for a forger to generate dissimilar images with the same features. On the other hand, the class of hash-based algorithms utilizes a cryptographic digital signature scheme and inherits the security of digital signatures to thwart forgery attacks. The main disadvantage of hash-based algorithms is that the image needs to be modified in order to be made authenticatable. We propose a multimedia authentication scheme which combines some of the best features of these two classes of algorithms. The proposed scheme utilizes cryptographic digital signature schemes and the data does not need to be modified in order to be made authenticatable. We show how results in sphere packings and coverings can be useful in the design. Several applications including the authentication of images on CD-ROM and handwritten documents are discussed. View full abstract»

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  • The plenoptic illumination function

    Publication Year: 2002 , Page(s): 361 - 371
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (395 KB)  

    Image-based modeling and rendering has been demonstrated as a cost-effective and efficient approach to virtual reality applications. The computational model that most image-based techniques are based on is the plenoptic function. Since the original formulation of the plenoptic function does not include illumination, most previous image-based virtual reality applications simply assume that the illumination is fixed. We propose a formulation of the plenoptic function, called the plenoptic illumination function, which explicitly specifies the illumination component. Techniques based on this new formulation can be extended to support relighting as well as view interpolation. To relight images with various illumination configurations, we also propose a local illumination model, which utilizes the rules of image superposition. We demonstrate how this new formulation can be applied to extend two existing image-based representations, panorama representation such as QuickTime VR and two-plane parameterization, to support relighting with trivial modifications. The core of this framework is compression, and we therefore show how to exploit two types of data correlation, the intra-pixel and the inter-pixel correlations, in order to achieve a manageable storage size. View full abstract»

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  • Index rendering: hardware-efficient architecture for 3-D graphics in multimedia system

    Publication Year: 2002 , Page(s): 343 - 360
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (642 KB) |  | HTML iconHTML  

    Real-time three-dimensional (3D) graphics is emerging rapidly in multimedia applications, but it suffers from requirements for huge computation, high bandwidth, and large buffer. In order to achieve hardware efficiency for 3D graphics rendering, we propose a novel approach named index rendering. The basic concept of index rendering is to realize a 3D rendering pipeline by using asynchronous multi-dataflows. Triangle information can be divided into several parts with each part capable of being transferred independently and asynchronously. Finally, all data are converged by the index to generate the final image. The index rendering approach can eliminate unnecessary operations in the traditional 3D graphics pipeline, the unnecessary operations are caused by the invisible pixels and triangles in the 3D scene. Previous work, deferred shading, eliminates the operations relating to invisible pixels, but it requires huge tradeoffs in bandwidth and buffer size. With index rendering, we can eliminate operations on both invisible pixels and triangles with fewer tradeoffs as compared with the deferred shading approach. The simulation and analysis results show that the index rendering approach can reduce 10%-70% of lighting operations when using the flat and Gouraud shading process and decrease 30%-95% when using Phong shading. Furthermore, it saves 70% of buffer size and 50%-70% of bandwidth compared with the deferred shading approach. The result also indicates that this approach of index rendering is especially suitable for low-cost portable rendering devices. Hence, index rendering is a hardware-efficient architecture for 3D graphics, and it makes rendering hardware more easily integrated into multimedia systems, especially system-on-a-chip (SOC) designs. View full abstract»

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Aims & Scope

The scope of the Periodical is the various aspects of research in multimedia technology and applications of multimedia.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Chang Wen Chen
State University of New York at Buffalo